Amylbenzoic acid and process for preparing same



Patented Oct. 10, 1933 AMYLEENZQIC ACID AND PROCESS FOR I PREPARINGSAMIE Herman A. Eruscn, Jack D. Robinson, and Otto Stein, Philadelphia,Pa, assigncrs to The Resinous Products & Chemical Co. Inc.-,Philadelphia, Pa.,

, No Drawing. Application July 25,

Serial No. 553,138

3 Claims. (01. ace-40s) This invention describes a method for prepar ingamylbenzoic acid, more particularly the compound which is believedto bep-(Z-amyl) -benzoic acid, a new substance having the formula One objectof this invention is to produce p- 1 (2-amylD-benzoic acid in good yieldby an economical process. Another object of this inven tion isto'producea technical mixture of isomeric amylbenzoic acids containing anypossible isomers, i. e. not only the secondary amyl group 5 but also thetertiary amyl group, iso-amyl group and so forth, as well as the orthosubstituted benzoic acids. These acids are to be used primarily for themanufacture of their polyvalent metal salts which are eflicientsiccatives for drying oil compositions as set forth in a copendingapplication of applicant Bruson, Serial No. 381,- 682, and in thepharmaceutical and dyestuffs industry.

The above acids may be prepared accordingto the presentinvention bytreating for example, para-amylacetophenone,

with hot alkaline hypochlorite or hypobromite solution. The amylacetophenones used for this purpose are new compounds, the manufactureand properties'of whichare described in a copending patent applicationSerial No. 537,496.

The following illustrates the manner of preparing amylbenzoic acid.

Example 1 40 In a vessel equipped with a vigorous stirrer and eficientreflux condenser is placed a solution of sodium hypochlorite, preparedby absorbing 82 grams of chlorine in a solution of 125 grams sodiumhydroxide in 750 cubic centimeters of water.

reaction. Upon cooling, any oily material is separated and the cl aralkaline solution acidified with dilute sulfuric acid. p(2-amyl -benzoicacid separates out as a yellowish oil which is. taken up in any suitableorganic solvent which is immiscible with water, suchas ether, benzene,naphtha, or ethylene dichloride. Upon evaporation of the solventand-fractionation of the residual oil in vacuo, p-(2-amyl).-benzoic acidcomes over as an almost colorless somewhat viscous oil, whichcrystallizes only with difficulty and boils at 140 C. under 3 m. in.pressure of mercury. The yield varies from 65 to of the theoretical. Itis readily soluble in almost all organic solvents such as alcohol,petroleum ether, ben- 70 zene, acetone, chloroform but ispracticallyinsoluble inwater. Its polyvalent metal salts such as thealuminum, antimony, barium, bismuth, cadmium, calcium, cerium, chromium,cobalt, copper, iron,v lead, magnesium, manganese, mercury, 7 strontium,nickel, thallium, tin, titanium, uranium, vanadium, and zinc salts arecharacterized I by the-fact that they are practically insoluble in Waterand readily soluble in a variety of organic solvents, notably benzene,solvent naphtha, turpentine, ethyl acetate, toluene, and in oils such aslinseed oil and other drying andsemi-drying oils.

Example 2 Instead of using p(2-amyl)-acetophenone as described inExample 1 above, one may use the same quantity of mixed isomericamyl-acetophenones which is a liquid boiling at 133- 136? C. at 8 m. m.

It is obtained by first condensing benzene with the mixed amylmcnochlorides or amyl alcohols (Pentasol) derived from the chlorinationof pentane. This mixture contains both primary-, secondary-, tertiary-,and iso-amyl benzenes which upon further treatment with acetyl chlorideor acetic anhydride and anhydrous aluminum chloride forms mixedamyl-acetophenones. These are described in a copending applicationSerial No. 537,496.

The mixed amylbenzoic acids obtained therefrom in accordance with theprocess described in Example 1, have a boiling point range of 150-160"C. at 4. m. m. pressure. Physically and chemically this mixtureresembles p-(2eamyl) benzoic acid, of which it contains a considerableamount. Upon refractionation it yields a main fraction boiling at155-157 C./4 m. m.

Its polyvalent metal salts possess the same unique solubilities asdescribed in Example 1.

Example 3 amyl-acetophenones. The oxidation was carried,

out by mixing 95 gr. of amyl-acetophenone (mixed hinder the reaction sothat it is preferable to use the sodium or potassium hypohalite.

The amyl-acetophenone may be replaced by an equivalent amount of anyother amyl-substituted acetophenone such as amyl-methyl-acetophenone,amyl-ethyl acetophenone, amyl-chlorphenyl-methyl ketone and the like.

The quantity of hypochlorite or hypobromite is preferably from 10 to inexcess of the theoretical quantityv required assuming that one mole ofthe ketone requires three moles of hypohalite in accordance with thefollowing reaction:

isomers) with 200 com. of this sodium hypochlorite in a 3 liter vesselfitted with stirrer and reflux condenser. The mixture was heated to90-100 C. until the reaction started. Heat was then shut ofi and theremainder of the hypochlorite solution allowed to run in slowly so thatthe mixture kept refluxing due to its own heat of reaction. After about25 hours the reaction was completed. The colorless clear solution wasseparated from any chloroform and the amylbenzoic acid was precipitatedby the addition of dilute sulfuric acid. The yield was of thetheoretical of mixed amylbenzoic acid isomers boiling at about 155 0/4m. m.

By using 95 grams of p-(Z-amyD-acetophenone in the above reaction,pJZ-amyD-benzoic acid was obtained in 60% yield, boiling at 140 C./ 3mm.

I Example 4 95 grams p-(2-amyl)-acetophenone is treated under refluxwith an alkaline hypobromite solution prepared by treating a solution of216 gr. sodium hydroxide in 2 liters water with 288 gr. bromine at 5-10C. The materials react vigorously at -95 C. When the reaction hasmoderated, the mixture is boiled four to five hours to complete thereaction. Any excess of hypobromite is then destroyed by adding a solu-.tion of sodium bisulfite. The bromoform is removed and the clearfiltrate acidified with dilute mineral acid. The p-(Z-amyD-benzoio acidis removed and fractionated as above in vacuo. The yield is 69% oftheoretical.

In the above reactions the sodium hypochlo rite may be replaced by anyalkaline hypochlorite or hypobromite in alkaline solution, e. g.

potassium or calcium hypochlorite. In the latter case, insoluble calciumsalts are formed which What we claim is:

1. As a new compound, p-(Z-amyD-benzoic acid.

2. As a new composition of matter, a mixture of isomeric amylbenzoicacids containing p-(2- amyl) -benzoic acid as the principal component.

3. In the process for preparing amylbenzoic acid, the step whichcomprises reacting an amylacetophenone in an alkaline solution with asalt of a member of the group consisting of hypochlorous and hypobromousacids.

4. In the process for preparing amylbenzoic acid, the step whichcomprises reacting an amylacetophenone with alkaline sodium hypochloritesolution. p

5. In the process for preparing p-(2-amyl). benzoic acid, the'step whichconsists in boiling p-(2-amyl)acetophenone with reacting proportions ofalkali metal hypochlorite solution and thereafter acidifying themixture.

6. In the process for preparing mixed isomeric amyl benzoic acids, thestep which consists in boiling mixed isomeric amyl acetophenones withreacting proportions ofalkali metal hypochlorite solution and thereafteracidifying the mixture.

'7. As a new compound p-(Z-amyl) -benzoic acid boiling at about 140 C.under 3 mm. pressure and characterized in that its anhydrous neutrallead salt is readily soluble in benzene.

8. As a new composition of matter, mixed isomeric amylbenzoic acidsboiling substantially at 133-136 C. under 8 mm. pressure, said mixturecontaining p-(2-amyl) -benzoic acid as the principal component, andcharacterized in that its anhydrous neutral lead salt is readily solublein benzene.

- HERMAN A. BRUSON.

JACKD. ROBINSON. OTTO STEIN.

